PARENT SESSION
Tuesday, August 8, 8:00-11:30 am
COS 30 - Invertebrate ecology
L-5, L-6, L-7, Lobby Level, Cook Convention Center
Presiders: C Johnson

Estimating rare butterfly abundance by combining multiple data types with simple population models.

Gross, Kevin^*,1, Haddad, Nick¹, Hudgens, Brian¹, Kalendra, Eric¹, ¹ North Carolina State University, Raleigh, NC

ABSTRACT- Many butterfly populations are monitored by regular surveys in which observers count the number of individuals seen while walking established transects. For species with non-overlapping generations, each adult flight period yields a time series of counts. Current methods combine these transect count data with models of the processes governing butterfly dynamics to estimate an index of total butterfly abundance. Here, we modify these methods to accommodate both stochastic population dynamics and data from other sources that provide information about detectability. These modifications produce an absolute measure of abundance instead of an index, as well as more accurate measures of the uncertainty in the estimated abundance. We illustrate our method with monitoring data for St. Francis satyr (Neonympha mitchelli), a rare butterfly occurring in the sandhills region of south-central North Carolina, USA.

Key words: abundance estimation, St. Francis satyr, conservation ecology